/*******************************************************************************
 * Copyright (c) 2011 MadRobot.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser Public License v2.1
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * 
 * Contributors:
 *  Elton Kent - initial API and implementation
 ******************************************************************************/
package com.madrobot.reflect;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;

import com.madrobot.text.StringUtils;

/**
 * <p>
 * Operates on classes without using reflection.
 * </p>
 * 
 * <p>
 * This class handles invalid <code>null</code> inputs as best it can. Each
 * method documents its behaviour in more detail.
 * </p>
 * 
 * <p>
 * The notion of a <code>canonical name</code> includes the human readable name
 * for the type, for example <code>int[]</code>. The non-canonical method
 * variants work with the JVM names, such as <code>[I</code>.
 * </p>
 */
public class ClassUtils {

	/**
	 * <p>
	 * The package separator character: <code>'&#x2e;' == {@value}</code>.
	 * </p>
	 */
	public static final char PACKAGE_SEPARATOR_CHAR = '.';

	/**
	 * <p>
	 * The package separator String: <code>"&#x2e;"</code>.
	 * </p>
	 */
	public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);

	/**
	 * <p>
	 * The inner class separator character: <code>'$' == {@value}</code>.
	 * </p>
	 */
	public static final char INNER_CLASS_SEPARATOR_CHAR = '$';

	/**
	 * <p>
	 * The inner class separator String: <code>"$"</code>.
	 * </p>
	 */
	public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);

	/**
	 * Maps primitive <code>Class</code>es to their corresponding wrapper
	 * <code>Class</code>.
	 */
	private static final Map<Class<?>, Class<?>> primitiveWrapperMap = new HashMap<Class<?>, Class<?>>();
	static{
		primitiveWrapperMap.put(Boolean.TYPE, Boolean.class);
		primitiveWrapperMap.put(Byte.TYPE, Byte.class);
		primitiveWrapperMap.put(Character.TYPE, Character.class);
		primitiveWrapperMap.put(Short.TYPE, Short.class);
		primitiveWrapperMap.put(Integer.TYPE, Integer.class);
		primitiveWrapperMap.put(Long.TYPE, Long.class);
		primitiveWrapperMap.put(Double.TYPE, Double.class);
		primitiveWrapperMap.put(Float.TYPE, Float.class);
		primitiveWrapperMap.put(Void.TYPE, Void.TYPE);
	}

	/**
	 * Maps wrapper <code>Class</code>es to their corresponding primitive types.
	 */
	private static final Map<Class<?>, Class<?>> wrapperPrimitiveMap = new HashMap<Class<?>, Class<?>>();
	static{
		for(Class<?> primitiveClass : primitiveWrapperMap.keySet()){
			Class<?> wrapperClass = primitiveWrapperMap.get(primitiveClass);
			if(!primitiveClass.equals(wrapperClass)){
				wrapperPrimitiveMap.put(wrapperClass, primitiveClass);
			}
		}
	}

	/**
	 * Maps a primitive class name to its corresponding abbreviation used in
	 * array class names.
	 */
	private static final Map<String, String> abbreviationMap = new HashMap<String, String>();

	/**
	 * Maps an abbreviation used in array class names to corresponding primitive
	 * class name.
	 */
	private static final Map<String, String> reverseAbbreviationMap = new HashMap<String, String>();

	/**
	 * Add primitive type abbreviation to maps of abbreviations.
	 * 
	 * @param primitive
	 *            Canonical name of primitive type
	 * @param abbreviation
	 *            Corresponding abbreviation of primitive type
	 */
	private static void addAbbreviation(String primitive, String abbreviation) {
		abbreviationMap.put(primitive, abbreviation);
		reverseAbbreviationMap.put(abbreviation, primitive);
	}

	/**
	 * Feed abbreviation maps
	 */
	static{
		addAbbreviation("int", "I");
		addAbbreviation("boolean", "Z");
		addAbbreviation("float", "F");
		addAbbreviation("long", "J");
		addAbbreviation("short", "S");
		addAbbreviation("byte", "B");
		addAbbreviation("double", "D");
		addAbbreviation("char", "C");
	}

	/**
	 * <p>
	 * ClassUtils instances should NOT be constructed in standard programming.
	 * Instead, the class should be used as
	 * <code>ClassUtils.getShortClassName(cls)</code>.
	 * </p>
	 * 
	 * <p>
	 * This constructor is public to permit tools that require a JavaBean
	 * instance to operate.
	 * </p>
	 */
	private ClassUtils() {
		super();
	}

	/**
	 * Factory method that returns a new instance of the given Class. This
	 * is called at the start of the bean creation process and may be
	 * overridden to provide custom behavior like returning a cached bean
	 * instance.
	 * <p>
	 * A more refined class instance creation is defined in {@link ClassUtils#instantiate(Class, String)}
	 * </p>
	 * 
	 * @param <T>
	 *            The type of object to create
	 * @param c
	 *            The Class to create an object from.
	 * @return A newly created object of the Class.
	 * @throws InstantiationException
	 * @throws IllegalAccessException
	 */
	public static <T> T newInstance(Class<T> c) throws IllegalAccessException, InstantiationException {
		return c.newInstance();

	}

	// Short class name
	// ----------------------------------------------------------------------
	/**
	 * <p>
	 * Gets the class name minus the package name for an <code>Object</code>.
	 * </p>
	 * 
	 * @param object
	 *            the class to get the short name for, may be null
	 * @param valueIfNull
	 *            the value to return if null
	 * @return the class name of the object without the package name, or the
	 *         null value
	 */
	public static String getShortClassName(Object object, String valueIfNull) {
		if(object == null){
			return valueIfNull;
		}
		return getShortClassName(object.getClass());
	}

	/**
	 * <p>
	 * Gets the class name minus the package name from a <code>Class</code>.
	 * </p>
	 * 
	 * @param cls
	 *            the class to get the short name for.
	 * @return the class name without the package name or an empty string
	 */
	public static String getShortClassName(Class<?> cls) {
		if(cls == null){
			return StringUtils.EMPTY;
		}
		return getShortClassName(cls.getName());
	}

	/**
	 * <p>
	 * Gets the class name minus the package name from a String.
	 * </p>
	 * 
	 * <p>
	 * The string passed in is assumed to be a class name - it is not checked.
	 * </p>
	 * 
	 * @param className
	 *            the className to get the short name for
	 * @return the class name of the class without the package name or an empty
	 *         string
	 */
	public static String getShortClassName(String className) {
		if(className == null){
			return StringUtils.EMPTY;
		}
		if(className.length() == 0){
			return StringUtils.EMPTY;
		}

		StringBuilder arrayPrefix = new StringBuilder();

		// Handle array encoding
		if(className.startsWith("[")){
			while(className.charAt(0) == '['){
				className = className.substring(1);
				arrayPrefix.append("[]");
			}
			// Strip Object type encoding
			if(className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';'){
				className = className.substring(1, className.length() - 1);
			}
		}

		if(reverseAbbreviationMap.containsKey(className)){
			className = reverseAbbreviationMap.get(className);
		}

		int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
		int innerIdx = className.indexOf(INNER_CLASS_SEPARATOR_CHAR, lastDotIdx == -1 ? 0 : lastDotIdx + 1);
		String out = className.substring(lastDotIdx + 1);
		if(innerIdx != -1){
			out = out.replace(INNER_CLASS_SEPARATOR_CHAR, PACKAGE_SEPARATOR_CHAR);
		}
		return out + arrayPrefix;
	}

	// Package name
	// ----------------------------------------------------------------------
	/**
	 * <p>
	 * Gets the package name of an <code>Object</code>.
	 * </p>
	 * 
	 * @param object
	 *            the class to get the package name for, may be null
	 * @param valueIfNull
	 *            the value to return if null
	 * @return the package name of the object, or the null value
	 */
	public static String getPackageName(Object object, String valueIfNull) {
		if(object == null){
			return valueIfNull;
		}
		return getPackageName(object.getClass());
	}

	/**
	 * <p>
	 * Gets the package name of a <code>Class</code>.
	 * </p>
	 * 
	 * @param cls
	 *            the class to get the package name for, may be
	 *            <code>null</code>.
	 * @return the package name or an empty string
	 */
	public static String getPackageName(Class<?> cls) {
		if(cls == null){
			return StringUtils.EMPTY;
		}
		return getPackageName(cls.getName());
	}

	/**
	 * <p>
	 * Gets the package name from a <code>String</code>.
	 * </p>
	 * 
	 * <p>
	 * The string passed in is assumed to be a class name - it is not checked.
	 * </p>
	 * <p>
	 * If the class is unpackaged, return an empty string.
	 * </p>
	 * 
	 * @param className
	 *            the className to get the package name for, may be
	 *            <code>null</code>
	 * @return the package name or an empty string
	 */
	public static String getPackageName(String className) {
		if(className == null || className.length() == 0){
			return StringUtils.EMPTY;
		}

		// Strip array encoding
		while(className.charAt(0) == '['){
			className = className.substring(1);
		}
		// Strip Object type encoding
		if(className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';'){
			className = className.substring(1);
		}

		int i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
		if(i == -1){
			return StringUtils.EMPTY;
		}
		return className.substring(0, i);
	}

	// Superclasses/Superinterfaces
	// ----------------------------------------------------------------------
	/**
	 * <p>
	 * Gets a <code>List</code> of superclasses for the given class.
	 * </p>
	 * 
	 * @param cls
	 *            the class to look up, may be <code>null</code>
	 * @return the <code>List</code> of superclasses in order going up from this
	 *         one <code>null</code> if null input
	 */
	public static List<Class<?>> getAllSuperclasses(Class<?> cls) {
		if(cls == null){
			return null;
		}
		List<Class<?>> classes = new ArrayList<Class<?>>();
		Class<?> superclass = cls.getSuperclass();
		while(superclass != null){
			classes.add(superclass);
			superclass = superclass.getSuperclass();
		}
		return classes;
	}

	/**
	 * <p>
	 * Gets a <code>List</code> of all interfaces implemented by the given class
	 * and its superclasses.
	 * </p>
	 * 
	 * <p>
	 * The order is determined by looking through each interface in turn as
	 * declared in the source file and following its hierarchy up. Then each
	 * superclass is considered in the same way. Later duplicates are ignored,
	 * so the order is maintained.
	 * </p>
	 * 
	 * @param cls
	 *            the class to look up, may be <code>null</code>
	 * @return the <code>List</code> of interfaces in order, <code>null</code>
	 *         if null input
	 */
	public static List<Class<?>> getAllInterfaces(Class<?> cls) {
		if(cls == null){
			return null;
		}

		LinkedHashSet<Class<?>> interfacesFound = new LinkedHashSet<Class<?>>();
		getAllInterfaces(cls, interfacesFound);

		return new ArrayList<Class<?>>(interfacesFound);
	}

	/**
	 * Get the interfaces for the specified class.
	 * 
	 * @param cls
	 *            the class to look up, may be <code>null</code>
	 * @param interfacesFound
	 *            the <code>Set</code> of interfaces for the class
	 */
	private static void getAllInterfaces(Class<?> cls, HashSet<Class<?>> interfacesFound) {
		while(cls != null){
			Class<?>[] interfaces = cls.getInterfaces();

			for(Class<?> i : interfaces){
				if(interfacesFound.add(i)){
					getAllInterfaces(i, interfacesFound);
				}
			}

			cls = cls.getSuperclass();
		}
	}

	// Convert list
	// ----------------------------------------------------------------------
	/**
	 * <p>
	 * Given a <code>List</code> of class names, this method converts them into
	 * classes.
	 * </p>
	 * 
	 * <p>
	 * A new <code>List</code> is returned. If the class name cannot be found,
	 * <code>null</code> is stored in the <code>List</code>. If the class name
	 * in the <code>List</code> is <code>null</code>, <code>null</code> is
	 * stored in the output <code>List</code>.
	 * </p>
	 * 
	 * @param classNames
	 *            the classNames to change
	 * @return a <code>List</code> of Class objects corresponding to the class
	 *         names, <code>null</code> if null input
	 * @throws ClassCastException
	 *             if classNames contains a non String entry
	 */
	public static List<Class<?>> convertClassNamesToClasses(List<String> classNames) {
		if(classNames == null){
			return null;
		}
		List<Class<?>> classes = new ArrayList<Class<?>>(classNames.size());
		for(String className : classNames){
			try{
				classes.add(Class.forName(className));
			} catch(Exception ex){
				classes.add(null);
			}
		}
		return classes;
	}

	/**
	 * <p>
	 * Given a <code>List</code> of <code>Class</code> objects, this method
	 * converts them into class names.
	 * </p>
	 * 
	 * <p>
	 * A new <code>List</code> is returned. <code>null</code> objects will be
	 * copied into the returned list as <code>null</code>.
	 * </p>
	 * 
	 * @param classes
	 *            the classes to change
	 * @return a <code>List</code> of class names corresponding to the Class
	 *         objects, <code>null</code> if null input
	 * @throws ClassCastException
	 *             if <code>classes</code> contains a non-<code>Class</code>
	 *             entry
	 */
	public static List<String> convertClassesToClassNames(List<Class<?>> classes) {
		if(classes == null){
			return null;
		}
		List<String> classNames = new ArrayList<String>(classes.size());
		for(Class<?> cls : classes){
			if(cls == null){
				classNames.add(null);
			} else{
				classNames.add(cls.getName());
			}
		}
		return classNames;
	}

	// Is assignable
	// ----------------------------------------------------------------------
	/**
	 * <p>
	 * Checks if an array of Classes can be assigned to another array of
	 * Classes.
	 * </p>
	 * 
	 * <p>
	 * This method calls {@link #isAssignable(Class, Class) isAssignable} for
	 * each Class pair in the input arrays. It can be used to check if a set of
	 * arguments (the first parameter) are suitably compatible with a set of
	 * method parameter types (the second parameter).
	 * </p>
	 * 
	 * <p>
	 * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
	 * method takes into account widenings of primitive classes and
	 * <code>null</code>s.
	 * </p>
	 * 
	 * <p>
	 * Primitive widenings allow an int to be assigned to a <code>long</code>,
	 * <code>float</code> or <code>double</code>. This method returns the
	 * correct result for these cases.
	 * </p>
	 * 
	 * <p>
	 * <code>Null</code> may be assigned to any reference type. This method will
	 * return <code>true</code> if <code>null</code> is passed in and the
	 * toClass is non-primitive.
	 * </p>
	 * 
	 * <p>
	 * Specifically, this method tests whether the type represented by the
	 * specified <code>Class</code> parameter can be converted to the type
	 * represented by this <code>Class</code> object via an identity conversion
	 * widening primitive or widening reference conversion. See
	 * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>
	 * , sections 5.1.1, 5.1.2 and 5.1.4 for details.
	 * </p>
	 * 
	 * <p>
	 * <strong>Since Lang 3.0,</strong> this method will default behavior for
	 * calculating assignability between primitive and wrapper types
	 * <em>corresponding
	 * to the running Java version</em>; i.e. autoboxing will be the default
	 * behavior in VMs running Java versions >= 1.5.
	 * </p>
	 * 
	 * @param classArray
	 *            the array of Classes to check, may be <code>null</code>
	 * @param toClassArray
	 *            the array of Classes to try to assign into, may be
	 *            <code>null</code>
	 * @return <code>true</code> if assignment possible
	 */
	public static boolean isAssignable(Class<?>[] classArray, Class<?>[] toClassArray) {
		return isAssignable(classArray, toClassArray, true);
	}

	/**
	 * Try to create an instance of a named class.
	 * First try the classloader of "sibling", then try the system
	 * classloader then the class loader of the current Thread.
	 * 
	 * @param sibling
	 * @param className
	 * @return
	 * @throws InstantiationException
	 * @throws IllegalAccessException
	 * @throws ClassNotFoundException
	 */
	public static Object instantiate(Class sibling, String className) throws InstantiationException,
			IllegalAccessException, ClassNotFoundException {
		// First check with sibling's classloader (if any).
		ClassLoader cl = sibling.getClassLoader();
		if(cl != null){
			try{
				Class cls = cl.loadClass(className);
				return cls.newInstance();
			} catch(Exception ex){
				// Just drop through and try the system classloader.
			}
		}

		// Now try the system classloader.
		try{
			cl = ClassLoader.getSystemClassLoader();
			if(cl != null){
				Class cls = cl.loadClass(className);
				return cls.newInstance();
			}
		} catch(Exception ex){
			// We're not allowed to access the system class loader or
			// the class creation failed.
			// Drop through.
		}

		// Use the classloader from the current Thread.
		cl = Thread.currentThread().getContextClassLoader();
		Class cls = cl.loadClass(className);
		return cls.newInstance();
	}

	
	/**
	 * Return true if class a is either equivalent to class b, or
	 * if class a is a subclass of class b, i.e. if a either "extends"
	 * or "implements" b.
	 * Note tht either or both "Class" objects may represent interfaces.
	 * 
	 * @param a
	 * @param b
	 * @return
	 */
	public static boolean isSubclass(Class a, Class b) {
		// We rely on the fact that for any given java class or
		// primtitive type there is a unqiue Class object, so
		// we can use object equivalence in the comparisons.
		if(a == b){
			return true;
		}
		if(a == null || b == null){
			return false;
		}
		for(Class x = a; x != null; x = x.getSuperclass()){
			if(x == b){
				return true;
			}
			if(b.isInterface()){
				Class interfaces[] = x.getInterfaces();
				for(int i = 0; i < interfaces.length; i++){
					if(isSubclass(interfaces[i], b)){
						return true;
					}
				}
			}
		}
		return false;
	}

	/**
	 * <p>
	 * Checks if an array of Classes can be assigned to another array of
	 * Classes.
	 * </p>
	 * 
	 * <p>
	 * This method calls {@link #isAssignable(Class, Class) isAssignable} for
	 * each Class pair in the input arrays. It can be used to check if a set of
	 * arguments (the first parameter) are suitably compatible with a set of
	 * method parameter types (the second parameter).
	 * </p>
	 * 
	 * <p>
	 * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
	 * method takes into account widenings of primitive classes and
	 * <code>null</code>s.
	 * </p>
	 * 
	 * <p>
	 * Primitive widenings allow an int to be assigned to a <code>long</code>,
	 * <code>float</code> or <code>double</code>. This method returns the
	 * correct result for these cases.
	 * </p>
	 * 
	 * <p>
	 * <code>Null</code> may be assigned to any reference type. This method will
	 * return <code>true</code> if <code>null</code> is passed in and the
	 * toClass is non-primitive.
	 * </p>
	 * 
	 * <p>
	 * Specifically, this method tests whether the type represented by the
	 * specified <code>Class</code> parameter can be converted to the type
	 * represented by this <code>Class</code> object via an identity conversion
	 * widening primitive or widening reference conversion. See
	 * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>
	 * , sections 5.1.1, 5.1.2 and 5.1.4 for details.
	 * </p>
	 * 
	 * @param classArray
	 *            the array of Classes to check, may be <code>null</code>
	 * @param toClassArray
	 *            the array of Classes to try to assign into, may be
	 *            <code>null</code>
	 * @param autoboxing
	 *            whether to use implicit autoboxing/unboxing between primitives
	 *            and wrappers
	 * @return <code>true</code> if assignment possible
	 */
	public static boolean isAssignable(Class<?>[] classArray, Class<?>[] toClassArray, boolean autoboxing) {
		if(ArrayUtils.isSameLength(classArray, toClassArray) == false){
			return false;
		}
		if(classArray == null){
			classArray = ArrayUtils.EMPTY_CLASS_ARRAY;
		}
		if(toClassArray == null){
			toClassArray = ArrayUtils.EMPTY_CLASS_ARRAY;
		}
		for(int i = 0; i < classArray.length; i++){
			if(isAssignable(classArray[i], toClassArray[i], autoboxing) == false){
				return false;
			}
		}
		return true;
	}

	/**
	 * <p>
	 * Checks if one <code>Class</code> can be assigned to a variable of another
	 * <code>Class</code>.
	 * </p>
	 * 
	 * <p>
	 * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
	 * method takes into account widenings of primitive classes and
	 * <code>null</code>s.
	 * </p>
	 * 
	 * <p>
	 * Primitive widenings allow an int to be assigned to a long, float or
	 * double. This method returns the correct result for these cases.
	 * </p>
	 * 
	 * <p>
	 * <code>Null</code> may be assigned to any reference type. This method will
	 * return <code>true</code> if <code>null</code> is passed in and the
	 * toClass is non-primitive.
	 * </p>
	 * 
	 * <p>
	 * Specifically, this method tests whether the type represented by the
	 * specified <code>Class</code> parameter can be converted to the type
	 * represented by this <code>Class</code> object via an identity conversion
	 * widening primitive or widening reference conversion. See
	 * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>
	 * , sections 5.1.1, 5.1.2 and 5.1.4 for details.
	 * </p>
	 * 
	 * <p>
	 * <strong>Since Lang 3.0,</strong> this method will default behavior for
	 * calculating assignability between primitive and wrapper types
	 * <em>corresponding
	 * to the running Java version</em>; i.e. autoboxing will be the default
	 * behavior in VMs running Java versions >= 1.5.
	 * </p>
	 * 
	 * @param cls
	 *            the Class to check, may be null
	 * @param toClass
	 *            the Class to try to assign into, returns false if null
	 * @return <code>true</code> if assignment possible
	 */
	public static boolean isAssignable(Class<?> cls, Class<?> toClass) {
		return isAssignable(cls, toClass, true);
	}

	/**
	 * <p>
	 * Checks if one <code>Class</code> can be assigned to a variable of another
	 * <code>Class</code>.
	 * </p>
	 * 
	 * <p>
	 * Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
	 * method takes into account widenings of primitive classes and
	 * <code>null</code>s.
	 * </p>
	 * 
	 * <p>
	 * Primitive widenings allow an int to be assigned to a long, float or
	 * double. This method returns the correct result for these cases.
	 * </p>
	 * 
	 * <p>
	 * <code>Null</code> may be assigned to any reference type. This method will
	 * return <code>true</code> if <code>null</code> is passed in and the
	 * toClass is non-primitive.
	 * </p>
	 * 
	 * <p>
	 * Specifically, this method tests whether the type represented by the
	 * specified <code>Class</code> parameter can be converted to the type
	 * represented by this <code>Class</code> object via an identity conversion
	 * widening primitive or widening reference conversion. See
	 * <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>
	 * , sections 5.1.1, 5.1.2 and 5.1.4 for details.
	 * </p>
	 * 
	 * @param cls
	 *            the Class to check, may be null
	 * @param toClass
	 *            the Class to try to assign into, returns false if null
	 * @param autoboxing
	 *            whether to use implicit autoboxing/unboxing between primitives
	 *            and wrappers
	 * @return <code>true</code> if assignment possible
	 */
	public static boolean isAssignable(Class<?> cls, Class<?> toClass, boolean autoboxing) {
		if(toClass == null){
			return false;
		}
		// have to check for null, as isAssignableFrom doesn't
		if(cls == null){
			return !(toClass.isPrimitive());
		}
		// autoboxing:
		if(autoboxing){
			if(cls.isPrimitive() && !toClass.isPrimitive()){
				cls = primitiveToWrapper(cls);
				if(cls == null){
					return false;
				}
			}
			if(toClass.isPrimitive() && !cls.isPrimitive()){
				cls = wrapperToPrimitive(cls);
				if(cls == null){
					return false;
				}
			}
		}
		if(cls.equals(toClass)){
			return true;
		}
		if(cls.isPrimitive()){
			if(toClass.isPrimitive() == false){
				return false;
			}
			if(Integer.TYPE.equals(cls)){
				return Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass)
						|| Double.TYPE.equals(toClass);
			}
			if(Long.TYPE.equals(cls)){
				return Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
			}
			if(Boolean.TYPE.equals(cls)){
				return false;
			}
			if(Double.TYPE.equals(cls)){
				return false;
			}
			if(Float.TYPE.equals(cls)){
				return Double.TYPE.equals(toClass);
			}
			if(Character.TYPE.equals(cls)){
				return Integer.TYPE.equals(toClass) || Long.TYPE.equals(toClass)
						|| Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
			}
			if(Short.TYPE.equals(cls)){
				return Integer.TYPE.equals(toClass) || Long.TYPE.equals(toClass)
						|| Float.TYPE.equals(toClass) || Double.TYPE.equals(toClass);
			}
			if(Byte.TYPE.equals(cls)){
				return Short.TYPE.equals(toClass) || Integer.TYPE.equals(toClass)
						|| Long.TYPE.equals(toClass) || Float.TYPE.equals(toClass)
						|| Double.TYPE.equals(toClass);
			}
			// should never get here
			return false;
		}
		return toClass.isAssignableFrom(cls);
	}

	/**
	 * <p>
	 * Converts the specified primitive Class object to its corresponding
	 * wrapper Class object.
	 * </p>
	 * 
	 * <p>
	 * NOTE: From v2.2, this method handles <code>Void.TYPE</code>, returning
	 * <code>Void.TYPE</code>.
	 * </p>
	 * 
	 * @param cls
	 *            the class to convert, may be null
	 * @return the wrapper class for <code>cls</code> or <code>cls</code> if
	 *         <code>cls</code> is not a primitive. <code>null</code> if null
	 *         input.
	 * @since 2.1
	 */
	public static Class<?> primitiveToWrapper(Class<?> cls) {
		Class<?> convertedClass = cls;
		if(cls != null && cls.isPrimitive()){
			convertedClass = primitiveWrapperMap.get(cls);
		}
		return convertedClass;
	}

	/**
	 * <p>
	 * Converts the specified array of primitive Class objects to an array of
	 * its corresponding wrapper Class objects.
	 * </p>
	 * 
	 * @param classes
	 *            the class array to convert, may be null or empty
	 * @return an array which contains for each given class, the wrapper class
	 *         or
	 *         the original class if class is not a primitive. <code>null</code>
	 *         if null input.
	 *         Empty array if an empty array passed in.
	 * @since 2.1
	 */
	public static Class<?>[] primitivesToWrappers(Class<?>[] classes) {
		if(classes == null){
			return null;
		}

		if(classes.length == 0){
			return classes;
		}

		Class<?>[] convertedClasses = new Class[classes.length];
		for(int i = 0; i < classes.length; i++){
			convertedClasses[i] = primitiveToWrapper(classes[i]);
		}
		return convertedClasses;
	}

	/**
	 * <p>
	 * Converts the specified wrapper class to its corresponding primitive
	 * class.
	 * </p>
	 * 
	 * <p>
	 * This method is the counter part of <code>primitiveToWrapper()</code>. If
	 * the passed in class is a wrapper class for a primitive type, this
	 * primitive type will be returned (e.g. <code>Integer.TYPE</code> for
	 * <code>Integer.class</code>). For other classes, or if the parameter is
	 * <b>null</b>, the return value is <b>null</b>.
	 * </p>
	 * 
	 * @param cls
	 *            the class to convert, may be <b>null</b>
	 * @return the corresponding primitive type if <code>cls</code> is a
	 *         wrapper class, <b>null</b> otherwise
	 * @see #primitiveToWrapper(Class)
	 * @since 2.4
	 */
	public static Class<?> wrapperToPrimitive(Class<?> cls) {
		return wrapperPrimitiveMap.get(cls);
	}

	/**
	 * <p>
	 * Converts the specified array of wrapper Class objects to an array of its
	 * corresponding primitive Class objects.
	 * </p>
	 * 
	 * <p>
	 * This method invokes <code>wrapperToPrimitive()</code> for each element of
	 * the passed in array.
	 * </p>
	 * 
	 * @param classes
	 *            the class array to convert, may be null or empty
	 * @return an array which contains for each given class, the primitive class
	 *         or
	 *         <b>null</b> if the original class is not a wrapper class.
	 *         <code>null</code> if null input.
	 *         Empty array if an empty array passed in.
	 * @see #wrapperToPrimitive(Class)
	 * @since 2.4
	 */
	public static Class<?>[] wrappersToPrimitives(Class<?>[] classes) {
		if(classes == null){
			return null;
		}

		if(classes.length == 0){
			return classes;
		}

		Class<?>[] convertedClasses = new Class[classes.length];
		for(int i = 0; i < classes.length; i++){
			convertedClasses[i] = wrapperToPrimitive(classes[i]);
		}
		return convertedClasses;
	}

	// Inner class
	// ----------------------------------------------------------------------
	/**
	 * <p>
	 * Is the specified class an inner class or static nested class.
	 * </p>
	 * 
	 * @param cls
	 *            the class to check, may be null
	 * @return <code>true</code> if the class is an inner or static nested
	 *         class,
	 *         false if not or <code>null</code>
	 */
	public static boolean isInnerClass(Class<?> cls) {
		if(cls == null){
			return false;
		}
		return cls.getName().indexOf(INNER_CLASS_SEPARATOR_CHAR) >= 0;
	}

	// Class loading
	// ----------------------------------------------------------------------
	/**
	 * Returns the class represented by <code>className</code> using the
	 * <code>classLoader</code>. This implementation supports the syntaxes
	 * "<code>java.util.Map.Entry[]</code>", "<code>java.util.Map$Entry[]</code>
	 * ",
	 * "<code>[Ljava.util.Map.Entry;</code>", and "
	 * <code>[Ljava.util.Map$Entry;</code>".
	 * 
	 * @param classLoader
	 *            the class loader to use to load the class
	 * @param className
	 *            the class name
	 * @param initialize
	 *            whether the class must be initialized
	 * @return the class represented by <code>className</code> using the
	 *         <code>classLoader</code>
	 * @throws ClassNotFoundException
	 *             if the class is not found
	 */
	public static Class<?> getClass(ClassLoader classLoader, String className, boolean initialize)
			throws ClassNotFoundException {
		try{
			Class<?> clazz;
			if(abbreviationMap.containsKey(className)){
				String clsName = "[" + abbreviationMap.get(className);
				clazz = Class.forName(clsName, initialize, classLoader).getComponentType();
			} else{
				clazz = Class.forName(toCanonicalName(className), initialize, classLoader);
			}
			return clazz;
		} catch(ClassNotFoundException ex){
			// allow path separators (.) as inner class name separators
			int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);

			if(lastDotIndex != -1){
				try{
					return getClass(classLoader, className.substring(0, lastDotIndex)
							+ INNER_CLASS_SEPARATOR_CHAR + className.substring(lastDotIndex + 1),
							initialize);
				} catch(ClassNotFoundException ex2){
				}
			}

			throw ex;
		}
	}

	/**
	 * Returns the (initialized) class represented by <code>className</code>
	 * using the <code>classLoader</code>. This implementation supports
	 * the syntaxes "<code>java.util.Map.Entry[]</code>",
	 * "<code>java.util.Map$Entry[]</code>", "
	 * <code>[Ljava.util.Map.Entry;</code>",
	 * and "<code>[Ljava.util.Map$Entry;</code>".
	 * 
	 * @param classLoader
	 *            the class loader to use to load the class
	 * @param className
	 *            the class name
	 * @return the class represented by <code>className</code> using the
	 *         <code>classLoader</code>
	 * @throws ClassNotFoundException
	 *             if the class is not found
	 */
	public static Class<?> getClass(ClassLoader classLoader, String className)
			throws ClassNotFoundException {
		return getClass(classLoader, className, true);
	}

	/**
	 * Returns the (initialized) class represented by <code>className</code>
	 * using the current thread's context class loader. This implementation
	 * supports the syntaxes "<code>java.util.Map.Entry[]</code>",
	 * "<code>java.util.Map$Entry[]</code>", "
	 * <code>[Ljava.util.Map.Entry;</code>",
	 * and "<code>[Ljava.util.Map$Entry;</code>".
	 * 
	 * @param className
	 *            the class name
	 * @return the class represented by <code>className</code> using the current
	 *         thread's context class loader
	 * @throws ClassNotFoundException
	 *             if the class is not found
	 */
	public static Class<?> getClass(String className) throws ClassNotFoundException {
		return getClass(className, true);
	}

	/**
	 * Returns the class represented by <code>className</code> using the
	 * current thread's context class loader. This implementation supports the
	 * syntaxes "<code>java.util.Map.Entry[]</code>", "
	 * <code>java.util.Map$Entry[]</code>",
	 * "<code>[Ljava.util.Map.Entry;</code>", and "
	 * <code>[Ljava.util.Map$Entry;</code>".
	 * 
	 * @param className
	 *            the class name
	 * @param initialize
	 *            whether the class must be initialized
	 * @return the class represented by <code>className</code> using the current
	 *         thread's context class loader
	 * @throws ClassNotFoundException
	 *             if the class is not found
	 */
	public static Class<?> getClass(String className, boolean initialize) throws ClassNotFoundException {
		ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
		ClassLoader loader = contextCL == null ? ClassUtils.class.getClassLoader() : contextCL;
		return getClass(loader, className, initialize);
	}

	// Public method
	// ----------------------------------------------------------------------
	/**
	 * <p>
	 * Returns the desired Method much like <code>Class.getMethod</code>,
	 * however it ensures that the returned Method is from a public class or
	 * interface and not from an anonymous inner class. This means that the
	 * Method is invokable and doesn't fall foul of Java bug <a
	 * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4071957"
	 * >4071957</a>).
	 * 
	 * <code><pre>Set set = Collections.unmodifiableSet(...);
     *  Method method = ClassUtils.getPublicMethod(set.getClass(), "isEmpty",  new Class[0]);
     *  Object result = method.invoke(set, new Object[]);</pre></code>
	 * </p>
	 * 
	 * @param cls
	 *            the class to check, not null
	 * @param methodName
	 *            the name of the method
	 * @param parameterTypes
	 *            the list of parameters
	 * @return the method
	 * @throws NullPointerException
	 *             if the class is null
	 * @throws SecurityException
	 *             if a a security violation occured
	 * @throws NoSuchMethodException
	 *             if the method is not found in the given class
	 *             or if the metothod doen't conform with the requirements
	 */
	public static Method getPublicMethod(Class<?> cls, String methodName, Class<?> parameterTypes[])
			throws SecurityException, NoSuchMethodException {

		Method declaredMethod = cls.getMethod(methodName, parameterTypes);
		if(Modifier.isPublic(declaredMethod.getDeclaringClass().getModifiers())){
			return declaredMethod;
		}

		List<Class<?>> candidateClasses = new ArrayList<Class<?>>();
		candidateClasses.addAll(getAllInterfaces(cls));
		candidateClasses.addAll(getAllSuperclasses(cls));

		for(Class<?> candidateClass : candidateClasses){
			if(!Modifier.isPublic(candidateClass.getModifiers())){
				continue;
			}
			Method candidateMethod;
			try{
				candidateMethod = candidateClass.getMethod(methodName, parameterTypes);
			} catch(NoSuchMethodException ex){
				continue;
			}
			if(Modifier.isPublic(candidateMethod.getDeclaringClass().getModifiers())){
				return candidateMethod;
			}
		}

		throw new NoSuchMethodException("Can't find a public method for " + methodName + " "
				+ ArrayUtils.toString(parameterTypes));
	}

	// ----------------------------------------------------------------------
	/**
	 * Converts a class name to a JLS style class name.
	 * 
	 * @param className
	 *            the class name
	 * @return the converted name
	 */
	private static String toCanonicalName(String className) {
		className = StringUtils.deleteWhitespace(className);
		if(className == null){
			throw new NullPointerException("className must not be null.");
		} else if(className.endsWith("[]")){
			StringBuilder classNameBuffer = new StringBuilder();
			while(className.endsWith("[]")){
				className = className.substring(0, className.length() - 2);
				classNameBuffer.append("[");
			}
			String abbreviation = abbreviationMap.get(className);
			if(abbreviation != null){
				classNameBuffer.append(abbreviation);
			} else{
				classNameBuffer.append("L").append(className).append(";");
			}
			className = classNameBuffer.toString();
		}
		return className;
	}

	/**
	 * <p>
	 * Converts an array of <code>Object</code> in to an array of
	 * <code>Class</code> objects. If any of these objects is null, a null
	 * element will be inserted into the array.
	 * </p>
	 * 
	 * <p>
	 * This method returns <code>null</code> for a <code>null</code> input
	 * array.
	 * </p>
	 * 
	 * @param array
	 *            an <code>Object</code> array
	 * @return a <code>Class</code> array, <code>null</code> if null array input
	 * @since 2.4
	 */
	public static Class<?>[] toClass(Object[] array) {
		if(array == null){
			return null;
		} else if(array.length == 0){
			return ArrayUtils.EMPTY_CLASS_ARRAY;
		}
		Class<?>[] classes = new Class[array.length];
		for(int i = 0; i < array.length; i++){
			classes[i] = array[i] == null ? null : array[i].getClass();
		}
		return classes;
	}

	// Short canonical name
	// ----------------------------------------------------------------------
	/**
	 * <p>
	 * Gets the canonical name minus the package name for an <code>Object</code>
	 * .
	 * </p>
	 * 
	 * @param object
	 *            the class to get the short name for, may be null
	 * @param valueIfNull
	 *            the value to return if null
	 * @return the canonical name of the object without the package name, or the
	 *         null value
	 * @since 2.4
	 */
	public static String getShortCanonicalName(Object object, String valueIfNull) {
		if(object == null){
			return valueIfNull;
		}
		return getShortCanonicalName(object.getClass().getName());
	}

	/**
	 * <p>
	 * Gets the canonical name minus the package name from a <code>Class</code>.
	 * </p>
	 * 
	 * @param cls
	 *            the class to get the short name for.
	 * @return the canonical name without the package name or an empty string
	 * @since 2.4
	 */
	public static String getShortCanonicalName(Class<?> cls) {
		if(cls == null){
			return StringUtils.EMPTY;
		}
		return getShortCanonicalName(cls.getName());
	}

	/**
	 * <p>
	 * Gets the canonical name minus the package name from a String.
	 * </p>
	 * 
	 * <p>
	 * The string passed in is assumed to be a canonical name - it is not
	 * checked.
	 * </p>
	 * 
	 * @param canonicalName
	 *            the class name to get the short name for
	 * @return the canonical name of the class without the package name or an
	 *         empty string
	 * @since 2.4
	 */
	public static String getShortCanonicalName(String canonicalName) {
		return ClassUtils.getShortClassName(getCanonicalName(canonicalName));
	}

	// Package name
	// ----------------------------------------------------------------------
	/**
	 * <p>
	 * Gets the package name from the canonical name of an <code>Object</code>.
	 * </p>
	 * 
	 * @param object
	 *            the class to get the package name for, may be null
	 * @param valueIfNull
	 *            the value to return if null
	 * @return the package name of the object, or the null value
	 * @since 2.4
	 */
	public static String getPackageCanonicalName(Object object, String valueIfNull) {
		if(object == null){
			return valueIfNull;
		}
		return getPackageCanonicalName(object.getClass().getName());
	}

	/**
	 * <p>
	 * Gets the package name from the canonical name of a <code>Class</code>.
	 * </p>
	 * 
	 * @param cls
	 *            the class to get the package name for, may be
	 *            <code>null</code>.
	 * @return the package name or an empty string
	 * @since 2.4
	 */
	public static String getPackageCanonicalName(Class<?> cls) {
		if(cls == null){
			return StringUtils.EMPTY;
		}
		return getPackageCanonicalName(cls.getName());
	}

	/**
	 * <p>
	 * Gets the package name from the canonical name.
	 * </p>
	 * 
	 * <p>
	 * The string passed in is assumed to be a canonical name - it is not
	 * checked.
	 * </p>
	 * <p>
	 * If the class is unpackaged, return an empty string.
	 * </p>
	 * 
	 * @param canonicalName
	 *            the canonical name to get the package name for, may be
	 *            <code>null</code>
	 * @return the package name or an empty string
	 * @since 2.4
	 */
	public static String getPackageCanonicalName(String canonicalName) {
		return ClassUtils.getPackageName(getCanonicalName(canonicalName));
	}

	/**
	 * <p>
	 * Converts a given name of class into canonical format. If name of class is
	 * not a name of array class it returns unchanged name.
	 * </p>
	 * <p>
	 * Example:
	 * <ul>
	 * <li><code>getCanonicalName("[I") = "int[]"</code></li>
	 * <li>
	 * <code>getCanonicalName("[Ljava.lang.String;") = "java.lang.String[]"</code>
	 * </li>
	 * <li>
	 * <code>getCanonicalName("java.lang.String") = "java.lang.String"</code></li>
	 * </ul>
	 * </p>
	 * 
	 * @param className
	 *            the name of class
	 * @return canonical form of class name
	 * @since 2.4
	 */
	private static String getCanonicalName(String className) {
		className = StringUtils.deleteWhitespace(className);
		if(className == null){
			return null;
		} else{
			int dim = 0;
			while(className.startsWith("[")){
				dim++;
				className = className.substring(1);
			}
			if(dim < 1){
				return className;
			} else{
				if(className.startsWith("L")){
					className = className.substring(1, className.endsWith(";") ? className.length() - 1
							: className.length());
				} else{
					if(className.length() > 0){
						className = reverseAbbreviationMap.get(className.substring(0, 1));
					}
				}
				StringBuilder canonicalClassNameBuffer = new StringBuilder(className);
				for(int i = 0; i < dim; i++){
					canonicalClassNameBuffer.append("[]");
				}
				return canonicalClassNameBuffer.toString();
			}
		}
	}
}
